Condensed Consolidated Unaudited Statements of Shareholders' Equity - USD ($) $ in Thousands | Total | Common Stock, Class B Common Stock and Preferred Stock | Paid-In Capital | Accumulated Other Comprehensive Loss | Retained Earnings | Treasury Stock | Non-controlling Interest |
Beginning balance at Dec. 31, 2017 | $ 1,550,977 | $ 21,050 | $ 804,008 | $ (34,221) | $ 594,556 | $ (87,440) | $ 253,024 |
Beginning balance (in shares) at Dec. 31, 2017 | | 37,228,715 | | | | | |
Cumulative-effect adjustment at Dec. 31, 2017 | | | | 301 | (301) | | |
Net income | 42,377 | | | | 34,219 | | 8,158 |
Other comprehensive income (loss) | (5,741) | | | (3,649) | | | (2,092) |
Issuances of non-vested restricted shares of common stock | | $ 46 | (46) | | | | |
Issuances of non-vested restricted shares of common stock (in shares) | | 91,609 | | | | | |
Forfeitures of non-vested restricted shares of common stock | | $ (2) | 2 | | | | |
Forfeitures of non-vested restricted shares of common stock (in shares) | | (3,000) | | | | | |
Common stock contribution to 401(k) plan | 2,945 | $ 9 | 2,936 | | | | |
Common stock contribution to 401(k) plan (in shares) | | 17,318 | | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan | 4,341 | $ 19 | 4,322 | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan (in shares) | | 37,130 | | | | | |
Retirement of common stock | (914) | $ (3) | (911) | | | | |
Retirement of common stock (in shares) | | (5,041) | | | | | |
Share-based compensation | 4,400 | | 4,400 | | | | |
Cash dividends declared and paid on Common and Class B common stock | (46,581) | | | | (46,581) | | |
Distributions to non-controlling interest | (2,178) | | | | | | (2,178) |
Ending balance at Mar. 31, 2018 | 1,549,626 | $ 21,119 | 814,711 | (37,569) | 581,893 | (87,440) | 256,912 |
Ending balance (in shares) at Mar. 31, 2018 | | 37,366,731 | | | | | |
Beginning balance at Dec. 31, 2017 | 1,550,977 | $ 21,050 | 804,008 | (34,221) | 594,556 | (87,440) | 253,024 |
Beginning balance (in shares) at Dec. 31, 2017 | | 37,228,715 | | | | | |
Cumulative-effect adjustment at Dec. 31, 2017 | | | | 301 | (301) | | |
Net income | 150,641 | | | | | | |
Other comprehensive income (loss) | (10,302) | | | | | | |
Ending balance at Jun. 30, 2018 | 1,601,994 | $ 21,120 | 817,559 | (40,459) | 617,666 | (87,440) | 273,548 |
Ending balance (in shares) at Jun. 30, 2018 | | 37,367,632 | | | | | |
Beginning balance at Mar. 31, 2018 | 1,549,626 | $ 21,119 | 814,711 | (37,569) | 581,893 | (87,440) | 256,912 |
Beginning balance (in shares) at Mar. 31, 2018 | | 37,366,731 | | | | | |
Net income | 108,264 | | | | 89,957 | | 18,307 |
Other comprehensive income (loss) | (4,561) | | | (2,890) | | | (1,671) |
Issuances of non-vested restricted shares of common stock | | $ 4 | (4) | | | | |
Issuances of non-vested restricted shares of common stock (in shares) | | 8,500 | | | | | |
Forfeitures of non-vested restricted shares of common stock | | $ (2) | 2 | | | | |
Forfeitures of non-vested restricted shares of common stock (in shares) | | (5,000) | | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan | 1,601 | $ 6 | 1,595 | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan (in shares) | | 11,935 | | | | | |
Retirement of common stock | (2,499) | $ (7) | (2,492) | | | | |
Retirement of common stock (in shares) | | (14,534) | | | | | |
Share-based compensation | 3,747 | | 3,747 | | | | |
Cash dividends declared and paid on Common and Class B common stock | (54,184) | | | | (54,184) | | |
Ending balance at Jun. 30, 2018 | 1,601,994 | $ 21,120 | 817,559 | (40,459) | 617,666 | (87,440) | 273,548 |
Ending balance (in shares) at Jun. 30, 2018 | | 37,367,632 | | | | | |
Beginning balance at Dec. 31, 2018 | 1,601,713 | $ 21,167 | 832,121 | (45,968) | 627,969 | (87,440) | 253,864 |
Beginning balance (in shares) at Dec. 31, 2018 | | 37,461,643 | | | | | |
Net income | 43,804 | | | | 35,037 | | 8,767 |
Other comprehensive income (loss) | 4,195 | | | 2,783 | | | 1,412 |
Issuances of non-vested restricted shares of common stock | | $ 39 | (39) | | | | |
Issuances of non-vested restricted shares of common stock (in shares) | | 77,049 | | | | | |
Forfeitures of non-vested restricted shares of common stock | | $ (3) | 3 | | | | |
Forfeitures of non-vested restricted shares of common stock (in shares) | | (5,000) | | | | | |
Common stock contribution to 401(k) plan | 4,274 | $ 15 | 4,259 | | | | |
Common stock contribution to 401(k) plan (in shares) | | 30,715 | | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan | 1,125 | $ 4 | 1,121 | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan (in shares) | | 8,925 | | | | | |
Retirement of common stock | (428) | $ (1) | (427) | | | | |
Retirement of common stock (in shares) | | (2,985) | | | | | |
Share-based compensation | 4,537 | | 4,537 | | | | |
Cash dividends declared and paid on Common and Class B common stock | (59,965) | | | | (59,965) | | |
Ending balance at Mar. 31, 2019 | 1,599,255 | $ 21,221 | 841,575 | (43,185) | 603,041 | (87,440) | 264,043 |
Ending balance (in shares) at Mar. 31, 2019 | | 37,570,347 | | | | | |
Beginning balance at Dec. 31, 2018 | 1,601,713 | $ 21,167 | 832,121 | (45,968) | 627,969 | (87,440) | 253,864 |
Beginning balance (in shares) at Dec. 31, 2018 | | 37,461,643 | | | | | |
Net income | 151,714 | | | | | | |
Other comprehensive income (loss) | 8,847 | | | | | | |
Ending balance at Jun. 30, 2019 | 1,633,362 | $ 21,266 | 828,932 | (40,146) | 632,983 | (87,440) | 277,767 |
Ending balance (in shares) at Jun. 30, 2019 | | 37,659,852 | | | | | |
Beginning balance at Mar. 31, 2019 | 1,599,255 | $ 21,221 | 841,575 | (43,185) | 603,041 | (87,440) | 264,043 |
Beginning balance (in shares) at Mar. 31, 2019 | | 37,570,347 | | | | | |
Net income | 107,910 | | | | 90,155 | | 17,755 |
Other comprehensive income (loss) | 4,652 | | | 3,039 | | | 1,613 |
Issuances of non-vested restricted shares of common stock | | $ 13 | (13) | | | | |
Issuances of non-vested restricted shares of common stock (in shares) | | 26,354 | | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan | 1,951 | $ 9 | 1,942 | | | | |
Stock issuances from exercise of stock options and employee stock purchase plan (in shares) | | 15,807 | | | | | |
Retirement of common stock | (555) | $ (2) | (553) | | | | |
Retirement of common stock (in shares) | | (3,608) | | | | | |
Share-based compensation | 4,324 | | 4,324 | | | | |
Cash dividends declared and paid on Common and Class B common stock | (60,213) | | | | (60,213) | | |
Common stock issued for Dunphey & Associates Supply Co., Inc. | 7,450 | $ 25 | 7,425 | | | | |
Common stock issued for Dunphey & Associates Supply Co., Inc. (in shares) | | 50,952 | | | | | |
Investment in unconsolidated entity | 988 | | | | | | 988 |
Decrease in non-controlling interest in Carrier Enterprise II | (32,400) | | (25,768) | | | | (6,632) |
Ending balance at Jun. 30, 2019 | $ 1,633,362 | $ 21,266 | $ 828,932 | $ (40,146) | $ 632,983 | $ (87,440) | $ 277,767 |
Ending balance (in shares) at Jun. 30, 2019 | | 37,659,852 | | | | | |