Share-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 6,380	$ 3,846	$ 2,392
Unrecognized Compensation Cost	2,413
Unrecognized compensation cost not expected to be recognized	$ 0
Expiration date of 2007 Stock Incentive Plan	May 20, 2024
Outstanding:
Balance (in shares)	105,000	105,000
Granted (in shares)	0	0	0
Granted, weighted average exercise price (in dollars per share)	$ 0	$ 0	$ 0
Stock options exercised (in shares)	27,619	0	4,337
Exercised, weighted average exercise price (in dollars per share)	$ 12.90		$ 11.62
Balance (in shares)	77,000	105,000	105,000
Ending balance, weighted average exercise price (in dollars per share)	$ 16.29
Vested and expected to vest (in shares)	77,000	105,000	105,000
Exercisable (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	77,000	105,000	105,000
Weighted-average remaining contractual life of all exercisable options (in years)	4 months 20 days
Stock price per share (in dollars per share)	$ 16.20
Share-based compensation arrangement by share-based payment award, options, exercisable, intrinsic value	$ 0
Intrinsic value under share based compensation scheme	$ 85	$ 0	$ 18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, number of options (in shares)	77,000
Options outstanding, weighted average remaining contractual life (in years)	4 months 20 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 16.29
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 0	0	0
Unrecognized Compensation Cost	$ 0
Weighted Average Remaining Amortization Periods (in years)	0 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 6,263	$ 3,705	$ 2,261
Unrecognized Compensation Cost	$ 2,413
Weighted Average Remaining Amortization Periods (in years)	8 months 12 days
Exercisable (in shares)
Expected to vest	1,004,000	806,000	649,000
Outstanding:
Balance (in shares)	1,028,000	1,147,000	1,059,000
Granted (in shares)	353,000	349,000	336,000
Vested (in shares)	(155,000)	(182,000)	(146,000)
Cancelled or forfeited (in shares)	(222,000)	(286,000)	(102,000)
Balance (in shares)	1,004,000	1,028,000	1,147,000
Beginning balance, Weighted average grant-date fair value (in dollars per share)	$ 13.24	$ 12.75	$ 13.40
Granted, Weighted average grant-date fair value (in dollars per share)	11.35	13.60	13.48
Vested, Weighted average grant-date fair value (in dollars per share)	12.27	11.41	15.87
Forfeitures, Weighted average grant date fair value	13.19	12.89	17.45
Ending balance, Weighted average grant-date fair value (in dollars per share)	$ 12.74	$ 13.24	$ 12.75
Phantom Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 117	$ 141	$ 131
Unrecognized Compensation Cost	$ 0
Weighted Average Remaining Amortization Periods (in years)	0 years
Outstanding:
Balance (in shares)	132,000	119,000	107,000
Granted (in shares)	10,000	10,000	10,000
Dividend equivalents issued	3,000	3,000	2,000
Redeemed for common stock (in shares)	0	0	0
Balance (in shares)	145,000	132,000	119,000
Granted, Weighted average grant-date fair value (in dollars per share)	$ 11.71	$ 14.09	$ 13.12
Performance Vested Restricted Stock Units [Member] | Scheduled to Vest January 1, 2017 [Member]
Exercisable (in shares)
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Not Expected To Vest Outstanding Number	0
Expected to vest	192,000
Outstanding:
Balance (in shares)	192,000
Performance Vested Restricted Stock Units [Member] | Scheduled to Vest January 1, 2018 [Member]
Exercisable (in shares)
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Not Expected To Vest Outstanding Number	0
Expected to vest	202,000
Outstanding:
Balance (in shares)	202,000
Performance Vested Restricted Stock Units [Member] | Scheduled to Vest January 1, 2019 [Member]
Exercisable (in shares)
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Not Expected To Vest Outstanding Number	0
Expected to vest	213,000
Outstanding:
Balance (in shares)	213,000
1998 Stock Option Program [Member]
Outstanding:
Balance (in shares)	70,000
2007 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized under restricted stock, unrestricted stock, RSU's and stock options to officers, employees and non-employee directors (in shares)	6,500,000
Exercisable (in shares)
Available for future grants (in shares)	3,474,000