Weighted Average Shares Outstanding (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Jun. 24, 2014	Jun. 16, 2014
Weighted Average Shares Outstanding [Line Items]
Basic (in shares)	54,191,013	55,028,063	54,791,030
Dilutive effect of:
Diluted (in shares)	54,631,313	55,513,219	55,723,267
Incremental Common Shares Attributable to Conversion of Debt Securities	0	0	245,230
3.375% Convertible Notes [Member] | Convertible Debt [Member]
Dilutive effect of:
Convertible Note Repurchases, Par Value						$ 224
Convertible notes stated interest rate				3.375%		3.375%
Convertible notes					$ 55,412
Stock options [Member]
Dilutive effect of:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	262,336	214,032	89,924
Stock options [Member]
Dilutive effect of:
Shares attributable to share-based payment arrangements (in shares)	166,986	206,778	355,595
Performance share awards [Member]
Dilutive effect of:
Shares attributable to share-based payment arrangements (in shares)	273,314	278,378	319,704
Non Employee Director Deferred Stock Plan [Member]
Dilutive effect of:
Shares attributable to share-based payment arrangements (in shares)	0	0	11,708