Employee Benefit Plans - Benefit Obligation and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Plan assets:
Fair value at beginning of year	$ 59,096
Fair value at end of year	45,713	$ 59,096
Amounts recognized as assets and liabilities in the consolidated balance sheets:
Non-current liabilities	(73,683)	(81,012)
Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	78,859	85,279
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	92,384	82,151
Interest cost	2,940	3,279	$ 3,642
Benefits paid	(484)	(407)
Actuarial (gains) losses	(525)	14,344
Curtailments		(1,097)
Special termination benefits	860	1,838
Settlement charges	(10,554)	(7,724)
Projected benefit obligation at end of year	84,621	92,384	82,151
Plan assets:
Fair value at beginning of year	59,096	63,113
Actual return on plan assets	(2,345)	4,114
Company contributions	10,000
Benefits paid	(484)	(407)
Settlement charges	(10,554)	(7,724)
Fair value at end of year	45,713	59,096	63,113
Under funded status	(38,908)	(33,288)
Amounts recognized as assets and liabilities in the consolidated balance sheets:
Non-current liabilities	(38,908)	(33,288)
Total	(38,908)	(33,288)
Amounts recognized in accumulated other comprehensive loss consist of:
Net loss	27,502	27,247
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	46,428	45,617
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	52,374	48,572
Interest cost	1,713	1,685	1,637
Benefits paid	(251)	(253)
Actuarial (gains) losses	566	6,650
Curtailments		(53)
Special termination benefits	290	365
Settlement charges	(2,418)	(4,592)
Projected benefit obligation at end of year	52,274	52,374	$ 48,572
Plan assets:
Company contributions	2,669	4,845
Benefits paid	(251)	(253)
Settlement charges	(2,418)	(4,592)
Under funded status	(52,274)	(52,374)
Amounts recognized as assets and liabilities in the consolidated balance sheets:
Current liabilities	(17,500)	(4,650)
Non-current liabilities	(34,774)	(47,724)
Total	(52,274)	(52,374)
Amounts recognized in accumulated other comprehensive loss consist of:
Net loss	$ 22,731	$ 25,640