Income Taxes - Statutory Federal Tax Rate (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount									$ 25,587	$ 45,943	$ 31,891
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount									1,587	2,116	2,116
Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Amount									7,766	7,766	7,766
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount									(13,542)	(2,693)	6
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount									132	384	141
Income tax expense	$ 2,769	$ 7,564	$ (6,368)	$ (1,141)	$ 3,774	$ 8,226	$ 13,036	$ 8,716	$ 2,824	$ 33,752	$ 22,156
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent									35.00%	35.00%	35.00%