Stock-Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Restricted shares
Stock-based compensation
Vesting period	3 years
Changes in unvested awards, shares
Balance at the beginning of the period (in shares)	50
Granted (in shares)	33
Balance at the end of the period (in shares)	83
Changes in awards, Wtd Avg Grant Price
Balance at the beginning of the period (in dollars per share)	$ 31.35
Granted (in dollars per share)	$ 20.89
Balance at the end of the period (in dollars per share)	$ 27.24
Option awards
Stock-based compensation
Vesting period	4 years
Option share awards vest annually in increments (as a percent)	25.00%
Changes in option awards outstanding, Shares
Balance at the beginning of the period (in shares)	341
Granted (in shares)	59
Forfeited (in shares)	(23)
Balance at the end of the period (in shares)	377
Changes in option awards, Wtd Avg Ex. Price
Balance at the beginning of the period (in dollars per share)	$ 25.62
Granted (in dollars per share)	$ 20.89
Forfeited (in dollars per share)	$ (30.77)
Balance at the end of the period (in dollars per share)	$ 24.57