Fair Value of Financial Instruments (Details) (USD $) | Sep. 28, 2013 | Dec. 29, 2012 |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | $41,003,000 | ' |
Asset measured at, fair value | 40,644,000 | ' |
Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 41,003,000 | 37,866,000 |
Assets measured at fair value, Unrealized gains | 160,000 | 73,000 |
Assets measured at fair value, Unrealized losses | -519,000 | -239,000 |
Asset measured at, fair value | 40,644,000 | 37,700,000 |
Level 1 [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 4,900,000 | 2,538,000 |
Assets measured at fair value, Unrealized gains | 71,000 | 6,000 |
Assets measured at fair value, Unrealized losses | -108,000 | -114,000 |
Asset measured at, fair value | 4,863,000 | 2,430,000 |
Liabilities | ' | ' |
Liabilities measured at fair value, Adjusted cost | ' | 293,000 |
Liabilities measured at fair value, Unrealized gains | 0 | 0 |
Liabilities measured at fair value, Unrealized losses | 0 | 0 |
Liabilities measured at fair value | 79,000 | 293,000 |
Convertible Debt, Fair Value Disclosures | 79,000 | ' |
Level 1 [Member] | Deferred director stock units [Member] | Recurring [Member] | ' | ' |
Liabilities | ' | ' |
Liabilities measured at fair value, Adjusted cost | ' | 263,000 |
Liabilities measured at fair value, Unrealized gains | ' | 0 |
Liabilities measured at fair value, Unrealized losses | ' | 0 |
Liabilities measured at fair value | ' | 263,000 |
Level 1 [Member] | Phantom stock units [Member] | Recurring [Member] | ' | ' |
Liabilities | ' | ' |
Liabilities measured at fair value, Adjusted cost | ' | 30,000 |
Liabilities measured at fair value, Unrealized gains | 0 | 0 |
Liabilities measured at fair value, Unrealized losses | 0 | 0 |
Liabilities measured at fair value | 79,000 | 30,000 |
Convertible Debt, Fair Value Disclosures | 79,000 | ' |
Level 1 [Member] | Equity securities [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 1,363,000 | 602,000 |
Assets measured at fair value, Unrealized gains | 68,000 | 6,000 |
Assets measured at fair value, Unrealized losses | -84,000 | -86,000 |
Asset measured at, fair value | 1,347,000 | 522,000 |
Level 1 [Member] | Mutual funds [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 3,537,000 | 1,936,000 |
Assets measured at fair value, Unrealized gains | 3,000 | 0 |
Assets measured at fair value, Unrealized losses | -24,000 | -28,000 |
Asset measured at, fair value | 3,516,000 | 1,908,000 |
Level 2 [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 36,103,000 | 35,328,000 |
Assets measured at fair value, Unrealized gains | 89,000 | 67,000 |
Assets measured at fair value, Unrealized losses | -411,000 | -125,000 |
Asset measured at, fair value | 35,781,000 | 35,270,000 |
Level 2 [Member] | Corporate fixed income [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 23,705,000 | 18,270,000 |
Assets measured at fair value, Unrealized gains | 86,000 | 48,000 |
Assets measured at fair value, Unrealized losses | -299,000 | -105,000 |
Asset measured at, fair value | 23,492,000 | 18,213,000 |
Level 2 [Member] | Government securities [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | ' | 195,000 |
Assets measured at fair value, Unrealized gains | ' | 14,000 |
Assets measured at fair value, Unrealized losses | ' | 0 |
Asset measured at, fair value | ' | 209,000 |
Level 2 [Member] | Municipal bonds [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 3,989,000 | 4,525,000 |
Assets measured at fair value, Unrealized gains | 2,000 | 4,000 |
Assets measured at fair value, Unrealized losses | -27,000 | -15,000 |
Asset measured at, fair value | 3,964,000 | 4,514,000 |
Level 2 [Member] | Certificates of deposit [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 7,403,000 | 10,891,000 |
Assets measured at fair value, Unrealized gains | 1,000 | 1,000 |
Assets measured at fair value, Unrealized losses | 0 | 0 |
Asset measured at, fair value | 7,404,000 | 10,892,000 |
Level 2 [Member] | Asset backed securities [Member] | Recurring [Member] | ' | ' |
Assets | ' | ' |
Assets measured at fair value, Adjusted cost | 1,006,000 | 1,447,000 |
Assets measured at fair value, Unrealized gains | 0 | 0 |
Assets measured at fair value, Unrealized losses | -85,000 | -5,000 |
Asset measured at, fair value | $921,000 | $1,442,000 |